Mechanical reinforcement of hydrogels via bio-inspired mineralization

Abstract

Nanocomposites made of polymer networks and mineral particles lend great mechanical integrity to biological materials. This study aims to imitate these natural materials by creating a hydrogel mineralized with magnetite particles. We create a hydrogel of polyallylamine crosslinked via tannic acid molecules. Crosslinking is dependent upon pH as well as amounts of periodate and tannic acid. The addition of greater amounts of tannic acid and periodate at higher pH creates a more strongly crosslinked network, shown through rheological measurements as the gel's shear modulus increases. Upon mineralization, a 10²-10³ order of magnitude increase in shear modulus occurs. This work elucidates a method for nanocomposite hydrogel synthesis that creates a mechanically strong biocompatible material for future applications in bio-interfacing technology and drug delivery.